Impact and chemical resistant polycarbonate blend

ABSTRACT

Impact resistant polycarbonate blends, which may be extruded without pre-drying, are prepared from an aromatic polycarbonate, an aromatic polyester, a carbon monoxide polymer and a polyalkyleneoxide rubber, and optionally, a grafted copolymer or mixture of grafted copolymers.

FIELD OF THE INVENTION

This invention relates generally to polycarbonates, and moreparticularly, to impact resistant polymer blends containing apolycarbonate, a polyester, a carbon monoxide copolymer and apolyalkyleneoxide rubber; and optionally, a grafted copolymer or mixtureof grafted copolymers. The polycarbonate blends of the present inventionare additionally unique in that the blend and its components may bemixed without pre-drying, and yet the excellent physical and mechanicalproperties of the as-extruded product are preserved.

BACKGROUND OF THE INVENTION

Polycarbonates are well-known commercially available resinous materialshaving a variety of applications. They are typically prepared by thereaction of dihydroxy compounds with a carbonate precursor, such asphosgene, in the presence of a catalyst. Methods of direct phosgenation,interfacial condensation and transesterification, for the preparation ofpolycarbonates, are described in detail in "The Chemistry and Physics ofPolycarbonates", by H. Schnell, John Wiley & Co., N.Y., 1964.

Polycarbonates are high temperature, high performance engineeringthermoplastics having a combination of good thermal and mechanicalproperties, especially when prepared from one or more aromatic diols.The blending with polycarbonates of additional compounds, such as forexample, other thermoplastic resins, copolymer rubber compounds, and thelike, is commonly practiced in order to improve one or more propertiesof the homopolymer polycarbonate.

A blend of polycarbonate, polyester, and a third impact modifyingcomponent is known. U.S. Pat. Nos. 4,257,937 and 4,677,148 disclose theuse of acrylate and other rubber-containing impact modifiers in blendsof polycarbonate and polyester. U.S. Pat. Nos. 4,180,494 and 4,654,400disclose the incorporation of acrylate or butadiene based core-shellcopolymers as impact modifiers for polycarbonate/polyester blends. Thesereferences do not, however, suggest the incorporation of apolyalkyleneoxide rubber.

U.S. Pat. No. 4,221,889 discloses a copolymer of a divinyl polyester anda polymerizable monomer, such as styrene, additionally containing as atoughener a polyepihalohydrin or copolymer of epihalohydrin and amonomer having an epoxide group. During polymerization of theepihalohydrin, the epoxide group opens, forming a polymer chaincontaining ether oxygen atoms in its backbone. The reference does notteach the toughening of a homopolymer polyester by the addition ofpolyepihalohydrin. It likewise does not suggest that thepolyepihalohydrin might eliminate the usual requirement of drying theblend prior to extrusion, since the resinous blends disclosed in thereference are liquid when molded.

U.S. Pat. No. 4,444,950 discloses a blend of a polycarbonate, a rubbermodified copolymer such as an ABS rubber, and a third componentcopolymer comprising an unsaturated epoxide-containing monomer and anolefin. The third component is polymerized through the double bonds onboth the epoxide-containing monomer and the olefin, thereby resulting ina polymer chain having pendant epoxide groups and no ether linkages inits backbone.

U.S. Pat. No. 3,780,139 and 4,271,063 disclose polymers of ethylene,carbon monoxide and a third component such as vinyl acetate.

Finally, U.S. Pat. No. 4,554,315 discloses a blend of a polycarbonate, apolyester, a graft copolymer, and a polymeric modifier prepared from anolefinically unsaturated monomer having at least one epoxide group. Thispolymeric modifier likewise polymerizes through the olefinic unsaturatedsite, resulting in a polymer chain having pendant epoxide groups and noether linkages in its backbone.

SUMMARY OF THE INVENTION

The present invention is directed toward a novel impact resistant andchemically resistant polycarbonate blend, which additionally does notrequire pre-drying of either the blend components nor the blend itselfin order to preserve good mechanical properties, comprising an aromaticpolycarbonate, an aromatic polyester, a carbon monoxide polymer and apolyalkyleneoxide rubber having a T_(g) lower than 0° C. Thepolyalkyleneoxide rubber component of the present invention does notcontain pendant epoxide groups; it is essentially a linear polyetherformed by the opening of the epoxide group of the alkylene oxide monomerduring polymerization. The polymer blend may optionally contain agrafted copolymer or a mixture of grafted copolymers. The blendsurprisingly is highly impact resistant, and chemically resistant,having an especially high notched Izod impact resistance in thicksections, and does not require the usual process step of drying prior toextrusion.

The polycarbonate blends of the present invention exhibit high impactresistance, chemical resistance, temperature stability, and excellentthermoplastic engineering properties, making them particularly suitablefor producing molded plastic components.

DETAILED DESCRIPTION

The aromatic polycarbonates suitable for use in the present inventionare produced by any of the conventional processes known in the art forthe manufacture of polycarbonates. Generally, aromatic polycarbonatesare prepared by reacting one or more aromatic dihydric phenols with acarbonate precursor, such as for example phosgene, a haloformate or acarbonate ester.

A preferred method for preparing the aromatic polycarbonates suitablefor use in the present invention involves the use of a carbonyl halide,such as phosgene, as the carbonate precursor. This method involvespassing phosgene gas into a reaction mixture containing one or moreactivated dihydric phenols, or, in the case of nonactivated dihydricphenols, also including an acid acceptor, such as for example pyridine,dimethyl aniline, quinoline and the like. The acid acceptor may be usedundiluted or diluted with inert organic solvents, such as methylenechloride, chlorobenzene or 1,2-dichloroethane. Tertiary amines areadvantageous since they are good solvents as well as acid acceptorsduring the reaction.

The temperature at which the carbonyl halide reaction proceeds may varyfrom below 0° C. to about 100° C. The reaction proceeds satisfactorilyat temperatures from room temperature to 50° C. Since the reaction isexothermic, the rate of phosgene addition may be used to control thetemperature of the reaction. The amount of phosgene required willgenerally depend upon the amount of dihydric phenols present. Generallyspeaking, one mole of phosgene will react with one mole of dihydricphenol to form the polycarbonate and two moles of HCl. The HCl is inturn taken up by the acid acceptor.

Another method for preparing the aromatic polycarbonates useful in thepresent invention comprises adding phosgene to an alkaline aqueoussuspension of dihydric phenols. This is preferably done in the presenceof inert solvents such as methylene chloride, 1,2-dichloroethane and thelike. Quaternary ammonium compounds may be employed to catalyze thereaction.

Yet another method for preparing such aromatic polycarbonates involvesthe phosgenation of an agitated suspension of the anhydrous alkali saltsof aryl diols in a nonaqueous medium such as benzene, chlorobenzene ortoluene. The reaction is illustrated by the addition of phosgene to aslurry of the sodium salt of, for example, Bisphenol A in an inertpolymer solvent such as chlorobenzene. The organic solvent shouldpreferably be a polymer solvent.

Generally speaking, a haloformate such as the bis-haloformate ofBisphenol A may be used in place of phosgene as the carbonate precursorin any of the methods described above.

When a carbonate ester is used as the carbonate precursor in thepolycarbonate forming reaction, the materials are reacted attemperatures in excess of 100° C., for times varying from 1 to 15 hours.Under such conditions, ester interchange occurs between the carbonateester and the dihydric phenol used. The ester interchange isadvantageously consummated at reduced pressures on the order of fromabout 10 to about 100 millimeters of mercury, preferably in an inertatmosphere such as nitrogen or argon.

Although the polymer forming reaction may be conducted in the absence ofa catalyst, one may, if desired, employ a typical ester exchangecatalyst, such as metallic lithium, potassium, calcium or magnesium. Theamount of such catalyst, if used, is usually small, ranging from about0.001 percent to about 0.1 percent, based on the weight of the dihydricphenols employed.

In the solution methods of preparation, the aromatic polycarbonateemerges from the reaction in either a true or pseudo solution dependingon whether an aqueous base or pyridine is used as an acid acceptor. Thecopolymer may be precipitated from the solution by adding a polymernonsolvent, such as heptane or isopropanol. Alternatively, the polymersolution may be heated, typically under reduced pressure, to evaporatethe solvent.

A preferred aromatic polycarbonate is characterized by repeated unitscorresponding to the general formula: ##STR1## wherein X is a divalentC₁ -C₁₅ hydrocarbon radical, a single bond, --O--, --S--, --S₂ --,--SO--, --SO₂ --, or --CO--. Each aromatic ring may additionally contain1 or 2 substituents such as C₁ -C₄ hydrocarbon radicals or haloradicals. A most preferred aromatic polycarbonate is prepared form2,2-bis-(4-hydroxyphenyl)-propane (Bisphenol A).

The aforementioned methods of preparing aromatic polycarbonates are morefully set forth in U.S. Pat. Nos. 2,999,846, 3,028,365, 3,148,172,3,153,008, 3,248,414, 3,271,367, and 4,452,968, which are herebyincorporated by reference thereto.

By the term aromatic polycarbonate, as used in the present invention, isalso contemplated aromatic carbonate-siloxane block copolymers whosestructure and method of preparation are taught in U.S. Pat. Nos.4,569,970 and 4,657,898 which are incorporated herein in their entiretyby reference thereto, as well as mixtures of polycarbonates and aromaticcarbonate-siloxane block copolymers.

Also included in the term aromatic polycarbonate are thepolycarbonate/polyester copolymers of the types disclosed in U.S. Pat.Nos. 3,169,121, 4,105,633, 4,156,069, 4,260,731 and 4,287,787 which areincorporated herein in their entirety by reference thereto, as well asmixtures of polycarbonates and polycarbonate/polyester copolymers.

The aromatic polyesters suitable for use, according to the presentinvention, are generally prepared by condensing aromatic dicarboxylicacids with diols. Suitable dicarboxylic acids include, for example,terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid,diphenyletherdicarboxylic acid, diphenyldicarboxylic acid,diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid, andthe like. The diols suitable for preparation of the aromatic polyestersinclude, for example, ethylene glycol, 1,3-propylene glycol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, cyclohexane dimethylol,and the like.

A preferred polyester is characterized by repeated units correspondingto the general formula: ##STR2## wherein n is selected from the numbers2 through 6. A most preferred aromatic polyester is polyethyleneterephthalate.

By the term polyester, as used in the present invention, is alsocontemplated copolyesters, which may be prepared by cocondensing one ormore aromatic dicarboxylic acids with one or more diols.

Specific methods of preparing aromatic polyesters and copolyesters aremore fully set forth in U.S. Pat. Nos. 2,465,319 and 3,047,539, whichare hereby incorporated in their entirety by reference thereto.

The carbon monoxide polymers include copolymers of one or moreethylenically unsaturated monomers especially α-olefins such as ethylenewith carbon monoxide. Preferred carbon monoxide copolymers comprise from1 to 25 percent by weight, preferably 2 to 20 percent by weight carbonmonoxide. Also included are carbon monoxide graft copolymers, forexample copolymers prepared by grafting a mixture of carbon monoxide andethylene onto a polyethylene substrate. Techniques for the preparationof carbon monoxide polymers are well known in the art having beenpreviously taught in U.S. Pat. Nos. 3,248,359 and 4,143,096, theteachings of which are incorporated herein in their entirety byreference thereto.

The polyalkyleneoxide rubbers suitable for practicing the presentinvention are prepared by polymerizing alkylene oxides containing two ormore carbon atoms. Alternatively, the aforementioned alkylene oxides maybe copolymerized with each other, or with epoxide-containing monomers.Polyalkyleneoxide rubbers are characterized in that they haverubber-like properties; e.g., high yield under stress, good elasticrecovery, and a glass transition temperature lower than 0° C.

Alkylene oxide monomers containing at least two carbon atoms, suitablefor preparing the polyalkyleneoxide rubbers of the present invention,correspond to the general formula: ##STR3## wherein each R₁ isindependently a C₁ -C₁₀ alkyl or alkylene, or halo substituted alkyl oralkylene hydrocarbon radical, or hydrogen atom. These monomers areunique in that they polymerize to produce essentially linear polyethers:polymerization having occurred through the epoxide group.

Examples of alkylene oxide monomers include, but are not limited to,propylene oxide, butene-1 oxide, butylene oxide, cis- and trans-butene-2oxides, hexane-1 oxide, hexane-2 oxide, dodecene-1 oxide,epichlorohydrin, trichlorobutylene oxide and the like. Additionally,mixtures of alkylene oxides, or alkylene oxides plus other oxides suchas for example styrene oxide, may be used to prepare copolymers,terpolymers, etc. The polymerization of alkylene oxides may be promotedby contacting the monomers in the presence of an organo-metalliccatalyst, such as for example triethylaluminum, at a temperature ofabout -30° C. to about 150° C. (see U.S. Pat. No. 3,728,321,incorporated herein by reference thereto). A preferred alkylene oxidemonomer is propylene oxide.

Epoxide-containing monomers, suitable for copolymerizing with alkyleneoxide monomers to prepare the polyalkyleneoxide rubbers of the presentinvention, correspond to the general formula: ##STR4## wherein each R₂is independently hydrogen, or a C₁ -C₁₀ alkyl, alkenyl, alkoxy alkyl oralkoxy carbonyl radical, or halo substituted alkyl, alkenyl, alkoxyalkyl or alkoxy carbonyl radical. Where the epoxide-containing monomercontains ethylenic unsaturation, the resultant polyalkyleneoxide rubbermay subsequently be crosslinked.

Copolymerization, involving epoxide-containing monomers, likewise occursthrough the epoxide group; therefore, no pendant epoxide groups remainin the resultant polyalkyleneoxide rubber copolymer. Examples ofepoxide-containing monomers include, but are not limited to, glycidylethers, such as methyl glycidyl ether, ethyl glycidyl ether andisopropyl glycidyl ether; also glycidyl acrylate, glycidyl methacrylate,epichlorohydrin, trichlorobutylene oxide, and allyl glycidyl ether.Copolymerization between the alkylene oxide monomers having at least twocarbon atoms and the epoxide-containing monomers may be effected bycontacting the monomers in the presence of an organo-metallic catalystsuch as triethylaluminum at a temperature of about -30° C. to about 150°C. A preferred epoxide-containing monomer is allyl glycidyl ether.

The amount of epoxide-containing monomers that may be copolymerized withthe alkylene oxide monomers will vary, depending upon the nature of themonomers. Generally, the alkylene oxide monomers should comprise about50 percent to about 100 percent of the polyalkyleneoxide rubber;preferably about 70 percent to about 100 percent. The allowableproportion of each monomer will generally be that amount required togive good rubbery physical properties, e.g., having a Tg lower than 0°C. Polyalkyleneoxide rubbers containing pendant ethylenicallyunsaturated groups, prepared by copolymerizing alkylene oxide monomerswith epoxide-containing monomers having ethylenic unsaturation, maysubsequently be vulcanized by known methods.

A preferred polyalkyleneoxide rubber is a copolymer of propylene oxideand allyl glycidyl ether, sold by B. F. Goodrich under the trademarkPAREL® 58.

The polycarbonate blends of the present invention may optionally containa grafted copolymer or a mixture of grafted copolymers. Such copolymersgenerally have a Tg below about 0° C. and are introduced into thepolymer matrix so as to result in a substantially uniform distributionin the blend of polycarbonate, polyester and polyalkyleneoxide rubber.

The grafted copolymers of the present invention are generallycharacterized as having a core-shell structure, typically prepared bymeans of an emulsion polymerization process, or a core-matrix structure,typically prepared by a mass polymerization process. The graftedcopolymers of the present invention generally comprise about 5 percentto 95 percent by weight of an elastomeric rubber core, and about 95percent to about 5 percent by weight of either a rigid grafted-onthermoplastic polymer shell in the case of a core-shell copolymer, or agrafted-on thermoplastic polymer matrix in the case of a core-matrixcopolymer. Examples of suitable grafted copolymers of the core-shelltype are a methylmethacrylate/butadiene/styrene grafted copolymer (MBSrubber), and a butyl acrylate core-rigid thermoplastic shell copolymer.An example of a suitable grafted copolymer of the core-matrix type is anacrylonitrile/butadiene/styrene grafted copolymer (ABS copolymer).

The preferred grafted copolymers are generally obtained by polymerizingcertain monomers in the presence of an acrylate or diene rubber core. Bythe term diene rubber is meant homopolymers of conjugated dienes have 4to 8 carbon atoms such as butadiene, isoprene, piperylene, chloroprene,and copolymers of such dienes with other monomers, such as for example,acrylonitrile, methacrylonitrile, butyl acrylate, methyl methacrylate,styrene, α-methylstyrene, and the like. The rubber core may be at leastpartially crosslinked, or may contain thermoplastic polymer inclusionssuch as for example when mass polymerization is used to prepare thegrafted copolymer. The aforementioned certain monomers are grafted ontothe rubber core to form either the shell or matrix. At least one ofthese monomers is selected from the group including styrene and itsderivatives, such as for example α-methylstyrene, acrylic acids,methacrylic acids, acrylonitrile, methacrylonitrile, methyl acrylate,ethyl acrylate, n-butyl acrylate, isobutyl acrylate, methylmethacrylate, n-butyl methacrylate, isobutyl methacrylate, glycidylmethacrylate, maleic anhydride and the like. Preferred graftedcopolymers are MBS rubbers, butyl acrylate core-rigid shell copolymers,ABS copolymers, and butadiene/styrene/acrylonitrile core-shell typecopolymers.

Methods for preparing the grafted copolymers for use in the presentinvention are the known mass or emulsion polymerization processes asdisclosed in U.S. Pat. Nos. 3,509,237, 3,660,535, 3,243,481, 4,221,833,4,617,345 and 4,239,863, which are incorporated herein in their entiretyby reference thereto.

It must be noted that a blend consisting solely of an aromaticpolycarbonate, an aromatic polyester, the carbon monoxide polymer and agrafted copolymer or mixture of grafted copolymers (i.e., a blend notcontaining a polyalkyleneoxide rubber) does not exhibit the advantageouscharacteristics of the present invention. The aforementioned blendand/or its components must be dried prior to extrusion in order topreserve its good mechanical properties. By contrast, the presentinvention eliminates the need for pre-drying the components or the blendprior to extrusion.

The polycarbonate blend of the present invention comprises about 5percent to about 95 percent, preferably about 40 percent to about 85percent, of an aromatic polycarbonate, about 90 percent to about 5percent, preferably about 60 percent to about 15 percent, of an aromaticpolyester, from 1 percent to 30 percent, preferably 2 percent to 20percent of the carbon monoxide polymer and about 0.1 to about 20percent, preferably about 1 percent to about 10 percent of apolyalkyleneoxide rubber. The blend may optionally contain up to about40 percent, preferably up to about 30 percent of a grafted copolymer ormixture of grafted copolymers. The recited percentages are in relationto the total weight of the resinous blend. The components may be mixedin any order, by the use of any conventional mixing apparatus, thenimmediately extruded, thereby bypassing the usually required step ofdrying the components or the blend prior to extrusion. The inclusion ofthe polyalkyleneoxide rubber obviates the drying step, while producing ablended resin having superior physical properties. As-extruded, theblend has good chemical resistance and reduced notched Izod impactsensitivity, especially in thick sections. As is well recognized in theart, similar blends not containing a polyalkyleneoxide rubber require adrying step prior to extrusion if the mechanical properties are to bepreserved.

The polycarbonate blends of the present invention may furthermorecontain conventional thermoplastic polymer additives, such as forexample, fillers, thermal stabilizers, dyes, flame retarding agents,reinforcing agents, softeners, mold-release agents, seed-forming agents,pigments, plasticizers, antistatic agents, ultraviolet ray absorbers,lubricants, and the like.

The invention is more easily comprehended by reference to specificembodiments which are representative of the invention. It must beunderstood, however, the the specific embodiments are provided only forthe purposes of illustration and understanding, and that the inventionmay be practiced otherwise than as specifically illustrated anddescribed without departing from its spirit and scope.

EXAMPLES 1-8

Blends containing the ingredients listed in Table I (expressed aspercent by weight) were prepared by tumble mixing the components,without pre-drying, for about seven minutes. The blend componentsincluded: CALIBRE®300-10, an aromatic polycarbonate manufactured by TheDow Chemical Company; KODAK® 7741, a polyethylene terephthalatepolyester manufactured by Kodak; VITUF® 1006C, a polyethyleneterephthalate polyester manufactured by Goodyear: PAREL® 58, apolyalkyleneoxide rubber copolymer of propylene oxide and allyl glycidylether manufactured by Goodrich: PARALOID® 3607 and 3330, MBS rubbersmanufactured by Rohm & Haas: PETG®, a terephthalic acid/ethyleneglycol/cyclohexane dimethanol polyester copolymer manufactured by Kodak:epoxidized soybean oil: and IRGANOX® 1076, a thermal antioxidantstabilizer manufactured by Ciba Geigy.

Each blend, without first being dried, was extruded in a 34 mmcounter-rotating twin screw American Leistritz vented extruder. Theextruded pellets were subsequently dried then injection molded into testspecimens using a 75 ton Arburg molding machine.

Physical properties of the test specimens are reported in Table II.Chemical aging of the specimens was accomplished by submerging eachspecimen, while under a 0.5 percent strain, in a 60/40 mixture ofisooctane and toluene, a synthetic gasoline.

It is apparent from the results of Table II that the inventedcompositions are extremely tough and highly resilient to attack byhydrocarbon solvents. The resins would accordingly be usefully employedin the manufacture of molded parts for use in automotive applications.

                  TABLE I                                                         ______________________________________                                        COMPOSITIONS TESTED                                                                      Examples                                                                      1     2      3        4    5                                       ______________________________________                                        CALIBRE ® 300-10                                                                       74.7    74.7   64.8   54.8 59.8                                  polycarbonate                                                                 KODAK ® 7741                                                                           --      10.0   19.9   29.9 --                                    polyester                                                                     VITUF ® 1006C                                                                          11.0    --     --     --   19.9                                  polyester                                                                     PETG ®   --      --     --     --   5.0                                   PAREL ® 58                                                                             4.0     4.0    4.0    4.0  4.0                                   polyalkyleneoxide                                                             rubber                                                                        PARALOID ® 3607                                                                        7.0     7.0    7.0    7.0  7.0                                   MBS rubber                                                                    ECO          3.0     4.0    4.0    4.0  4.0                                   Epoxidized   0.1     0.1    0.1    0.1  0.1                                   Soybean Oil                                                                   IRGANOX ® 1076                                                                         0.2     0.2    0.2    0.2  0.2                                   antioxidant                                                                   ______________________________________                                    

                                      TABLE II                                    __________________________________________________________________________    PHYSICAL TEST PROPERTIES                                                                  Example                                                                            Example                                                                            Example                                                                            Example                                                                            Example                                                   1    2    3    4    5                                             __________________________________________________________________________    Perpendicular                                                                 Izod Impact, 1/8",                                                            10 mil. notch                                                                 ft-lbs/in @ 23° C.                                                                 7.5  7.1  7.8  8.5  8.1                                           @ 0° C.                                                                            6.3  5.9  6.5  7.2  7.2                                           Parallel Izod Impact,                                                         1/8" thickness,                                                               10 mil notch,                                                                 ft-lbs/in @ 23° C.                                                                 11.8 11.6 11.5 11.6 11.9                                          @ 0° C.                                                                            11.6 11.6 12.0 11.3 12.1                                          @ -21° C.                                                                          11.4 10.9 10.6 6.9  10.0                                          Tensile at Break,                                                                         7,948                                                                              7,230                                                                              7,839                                                                              7,316                                                                              7,134                                         psi, following 5 min                                                          @ 0.5% str. in 60/40                                                          Iso/Tol                                                                       % Elongation at                                                                           109  103  130  135  119                                           Break, following                                                              5 min @ 0.5% str.                                                             in 60/40 Iso/Tol                                                              __________________________________________________________________________

What is claimed is:
 1. A thermoplastic molding composition comprising:A.an aromatic polycarbonate; B. an aromatic polyester; C. a copolymer ofone or more ethylenically unsaturated monomers with carbon monoxide; andD. a polyalkylene oxide rubber having a glass transition temperature(Tg) lower than 0° C.
 2. The thermoplastic molding composition of claim1, wherein the polyalkyleneoxide rubber is prepared by polymerizing oneor more alkylene oxides of the general formula: ##STR5## wherein each R₁is independently a C₁ -C₁₀ alkyl or alkylene, or halo substituted alkylor alkylene hydrocarbon radical, or a hydrogen atom.
 3. Thethermoplastic molding composition of claim 2, wherein thepolyalkyleneoxide rubber is prepared by further copolymerizing, with thealkylene oxides, epoxide-containing monomers of the general formula:##STR6## wherein each R₂ is independently hydrogen, or a C₁ -C₁₀ alkyl,alkenyl, alkoxy alkyl or alkoxy carbonyl radical, or halo substitutedalkyl, alkenyl, alkoxy alkyl or alkoxy carbonyl radical.
 4. Thethermoplastic molding composition of claim 1, wherein the aromaticpolycarbonate is characterized at least in part by repeated unitscorresponding to the general formula: ##STR7## wherein X is a divalentC₁ -C₁₅ hydrocarbon radical, a single bond, --O--, --S--, --S₂ --,--SO--, --SO₂ --, or --CO--, and further wherein each aromatic ring mayoptionally contain 1 or 2 C₁ -C₄ hydrocarbon radical or halo radicalconstituents.
 5. The thermoplastic molding composition of claim 4,wherein the aromatic polycarbonate is prepared at least in part fromBisphenol A.
 6. The thermoplastic molding composition of claim 1,wherein the aromatic polyester is characterized at least in part byrepeated units corresponding to the general formula: ##STR8## wherein nis selected from the numbers 2 through
 6. 7. The thermoplastic moldingcomposition of claim 6, wherein the aromatic polyester is at least inpart polyethylene terephthalate.
 8. The thermoplastic moldingcomposition of claim 2, wherein the polyalkyleneoxide rubber is preparedat least in part from propylene oxide.
 9. The thermoplastic moldingcomposition of claim 3, wherein the polyalkyleneoxide rubber is preparedat least in part from propylene oxide, and allyl glycidyl ether.
 10. Thethermoplastic molding composition of claim 1 further comprising agrafted copolymer or mixture of grafted copolymers, wherein the graftedcopolymer or mixture thereof comprises:A. about 5 percent to abut 95percent by weight of an elastomeric rubber core; and B. about 5 percentto about 95 percent by weight of:i. a rigid grafted-on thermoplasticshell; or ii. a grafted-on thermoplastic polymer matrix.
 11. Thethermoplastic molding composition of claim 10, wherein the graftedcopolymer is an MBS (methyl methacrylate/butadiene/styrene) rubber, abutyl acrylate core-rigid shell copolymer, an ABS(acrylonitrile/butadiene/styrene) copolymer, abutadiene/styrene/acrylonitrile core-shell copolymer, or a mixturethereof.
 12. The thermoplastic molding composition of claim 3, whereinthe polyalkyleneoxide rubber is at least in part crosslinked.
 13. Thethermoplastic molding composition of claim 1, wherein the aromaticpolycarbonate comprises about 5 percent to about 95 percent, based uponthe total weight of polymers.
 14. The thermoplastic molding compositionof claim 13, wherein the aromatic polycarbonate comprises about 40percent to about 85 percent, based upon the total weight of polymers.15. The thermoplastic molding composition of claim 1, wherein thearomatic polyester comprises about 5 percent to about 90 percent, basedupon the total weight of polymers.
 16. The thermoplastic moldingcomposition of claim 15, wherein the aromatic polyester comprises about15 percent to about 60 percent, based upon the total weight of polymers.17. The thermoplastic molding composition of claim 1, wherein thepolyalkyleneoxide rubber comprises about 0.1 percent to about 20percent, based upon the total weight of polymers.
 18. The thermoplasticmolding composition of claim 17, wherein the polyalkyleneoxide rubbercomprises about 1 percent to about 10 percent, based upon the totalweight of polymers.
 19. The thermoplastic molding composition of claim10, wherein the grafted copolymer or mixture of grafted copolymerscomprises less than about 40 percent, based upon the total weight of thepolymers.
 20. The thermoplastic molding composition of claim 1, whereinthe carbon monoxide copolymer is a graft copolymer of carbon monoxideand one or more ethylenically unsaturated monomers onto a polyethylenesubstrate.